This work has for goals to determine the role leukocytes may play in blood coagulation and thrombosis. Investigate the circumstances which favor the development of the procoagulant activity. Develop methods of detection of this procoagulant activity. BIBLIOGRAPHIC REFERENCES: Niemetz, J. and Marcus, A.J.: The stimulatory effect of platelets and platelet membranes on the procoagulant activity of leukocytes. J. Clin. Invest. 54:1437-1443, 1974.